"There's not a team on the planet he could not play for. Take him out of any team and it's a loss," Coleman told reporters on Friday.
"We were without him for the first three games which was a blow for us, it would be a blow for anyone. It's disappointing and frustrating."
Wales have one win and two draws from their three qualifying matches and are third in the table, two points behind Serbia and Ireland.
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Ramsey, 25, was instrumental in his country's surge to the semi-finals of the European Championship earlier this year and has scored a total of 11 goals in 44 internationals.
With only the group winners automatically qualifying for the 2018 World Cup in Russia, Coleman will gamble on Ramsey's lack of match fitness against Serbia.
"However long he'll last physically we don't know but we do know he's generally probably one of the fittest players playing football," the 46-year-old said.
(Reporting by Debanjan Bose in Bengaluru; Editing by Tony Jimenez)
